The present invention relates to method and device for controlling a power steering apparatus wherein the power steering apparatus can be free from trouble even when it is abnormally operated for a long period of time.
Automatic transmission vehicles have recently become prevalent in favor of a light steering force. A power steering apparatus is generally controlled such that a rotational speed of a motor-driven oil pump changes in accordance with a vehicle speed or a steering angle so as to control an oil flow rate. In this case, an output from the power steering apparatus is inversely-proportional to the vehicle speed and is proportional to the steering angle. However, maximum output is not maintained for a long period of time in normal operation. In this sense, the power steering apparatus need not have a long-term maximum output rating for continuously generating the maximum output, but can have a short-term maximum output rating for generating the maximum output for only a required period of time. When the short-term maximum output rating is employed, a compact power steering apparatus can be provided, resulting in an economic advantage. Therefore, most of the conventional power steering apparatuses have a short-term maximum output rating.
However, when the steering wheel is subjected to stationary swing and is kept in this state for a long period of time, the power steering apparatus in this abnormal operation state is subjected to overload which it cannot withstand, resulting in trouble.